Mean field exponents and small quark masses

We demonstrate that the restoration of chiral symmetry at finite T in a cla ss of confining Dyson-Schwinger equation (DSE) models of QCD is a mean fiel d transition, and that an accurate determination of the critical exponents using the chiral and thermal susceptibilities requires very small values of the current-quark mass: log(10)(m/m(u)) less than or similar to -5. Other classes of DSE models characterized by qualitatively different interactions also exhibit a mean field transition. Incipient in this observation is the suggestion that mean field exponents are a result of the gap equation's fe rmion substructure and not of the interaction. [S0556-2813(99)02303-1].